Thanks to Fedora for the (simple) patch :)

--- gtk-chtheme-0.3.1/util.c~	2004-02-08 14:42:33.000000000 +0100
+++ gtk-chtheme-0.3.1/util.c	2010-07-14 10:40:18.000000000 +0200
@@ -19,7 +19,8 @@

 GtkWidget* unfocussable(GtkWidget *w)
 {
-	GTK_WIDGET_UNSET_FLAGS(w, GTK_CAN_FOCUS);
+        /* GTK_WIDGET_UNSET_FLAGS(w, GTK_CAN_FOCUS); */
+        gtk_widget_set_can_focus(w, FALSE);
 	return w;
 }

